Use of a Chirp Waveform in Pulsed Eddy Current Crack Detection
Is Version Of
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When an electrical conductor containing a surface-breaking crack is subjected to a short pulse of electromagnetic radiation, the reflected field contains transient features related to the depth of the crack. This has been demonstrated in both theoretical calculations  and in experiments [2,3] on shallow (0.13 mm to 1.3 mm) slots in a low conductivity titanium alloy. Specifically, these results show that the peak crack signal is delayed in time by an amount proportional to the square of the crack depth, and that the signal decay times also increase with increasing depth.